Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K49/00—Dynamo-electric clutches; Dynamo-electric brakes
  • H02K49/02—Dynamo-electric clutches; Dynamo-electric brakes of the asynchronous induction type
  • H02K49/04—Dynamo-electric clutches; Dynamo-electric brakes of the asynchronous induction type of the eddy-current hysteresis type
  • H02K49/043—Dynamo-electric clutches; Dynamo-electric brakes of the asynchronous induction type of the eddy-current hysteresis type with a radial airgap
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
  • B60L7/00—Electrodynamic brake systems for vehicles in general
  • B60L7/28—Eddy-current braking
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/60—Other road transportation technologies with climate change mitigation effect
  • Y02T10/64—Electric machine technologies in electromobility

Definitions

• the invention relates to a method for controlling an electromagnetic retarder comprising a current generator.
• the invention also relates to such an electromagnetic retarder.
• the invention applies to a retarder capable of generating a resistant retarding torque on a main or secondary drive shaft of a vehicle which it equips, when this retarder is actuated.
• Such an electromagnetic retarder comprises a rotary shaft which is coupled to the main or secondary transmission shaft of the vehicle to exert on it the resisting retarding torque in particular to assist braking of the vehicle.
• the slowdown is generated with field coils supplied with direct current to produce a magnetic field in a metal part made of ferromagnetic material, in order to cause eddy currents to appear in this metal part.
• the field coils can be fixed to cooperate with at least one metal part made of mobile ferromagnetic material having a general appearance of a disc rigidly secured to the rotary shaft.
• these field coils are generally oriented parallel to the axis of rotation and arranged around this axis, opposite the disc, being secured to a fixed flange. Two successive field coils are electrically powered to generate magnetic fields in opposite directions.
• the field coils are electrically powered by a current from the vehicle's electrical network, that is to say for example from a vehicle battery.
• a current generator is integrated into the retarder.
• the electrical supply of the induction coils is ensured by a generator comprising primary stator coils supplied by the vehicle network, and secondary rotor windings integral with the rotary shaft .
• the induction coils are integral with the rotary shaft, being radially projecting, to generate a magnetic field in a fixed cylindrical jacket which surrounds them.
• a rectifier such as a diode bridge rectifier is interposed between the secondary rotor windings and the field coils, also being carried by the rotary shaft. This rectifier converts the alternating current delivered by the secondary windings of the generator into direct current supplying the induction coils.
• Two consecutive inductor coils around the axis of rotation generate magnetic fields in opposite directions, one generating a field oriented centrifugally, the other a field oriented centripetally.
• the power supply to the primary coils allows the generator to produce the supply current to the field coils, which gives rise to eddy currents in the fixed cylindrical jacket, to generate a resistant torque on the rotating shaft, which slows down the vehicle.
• the speed of rotation of the retarder shaft is then overdriven with respect to the speed of rotation of the transmission shaft to which it is coupled. This arrangement makes it possible to significantly increase the electrical power delivered by the generator, and therefore the power of the retarder.
• Such a retarder is for example controlled by means of a lever or the like which can be actuated directly by an occupant of the vehicle.
• the engagement of the retarder thus consists in moving the lever in question towards an activation position.
• the object of the invention is to propose a method of commissioning such a retarder making it possible to increase its reliability and longevity.
• the subject of the invention is a method of commissioning an electromagnetic retarder comprising a current generator, consisting in establishing an excitation current in primary stator coils of this generator, this excitation current being injected from a control unit connected to an electrical power source, this electromagnetic retarder comprising a rotary shaft carrying secondary windings of the generator and field coils as well as a current rectifier, the field coils being supplied by the secondary coils via the rectifier, and in which the secondary windings have a time constant which is less than the time constant of the field coils and / or greater than the time constant of the primary coils, this method consisting in injecting into the primary coils a continuous excitation current having an intensity which gradually increases to a nominal value for a predetermined minimum duration.
• the gradual increase in the excitation current of the primary coils makes it possible to limit the overvoltage resulting from the transient effect due to the establishment of currents in the electrical elements located downstream of these primary coils.
• the invention also relates to a method as defined above, in which the predetermined minimum duration is greater than the time constant of the primary coils, the time constant of the secondary windings, and the time constant of the field coils.
• the invention also relates to a method as defined above, consisting in increasing the excitation current linearly during the predetermined minimum duration.
• the invention also relates to the application of a method as defined above, to a rectifier in which the rectifier device is a diode bridge.
• the invention also relates to an electromagnetic retarder comprising a current generator and a control unit intended to be connected to an electrical power source for electrically supplying the stator primary coils of this generator, this electromagnetic raiser comprising a rotary shaft carrying secondary windings of the generator and the inductor coils as well as a rectifier current, the field coils being supplied by the secondary coils via the rectifier, in which the secondary windings have a time constant which is less than the time constant of the field coils and / or greater than the time constant of the primary coils, and wherein the control unit comprises means for injecting into the primary coils a continuous excitation current having an intensity which progressively increases to a nominal value for a predetermined minimum duration.
• the invention also relates to an electromagnetic retarder as defined above, in which the rectifier is a diode bridge.
• Figure 1 is an overall view with local cutaway of an electromagnetic retarder to which the invention applies;
• Figure 2 is a schematic representation of the electrical components of the retarder according to the invention.
• the electromagnetic retarder 1 comprises a main casing 2 of generally cylindrical shape having a first end closed by a cover 3, and a second end closed by a coupling piece 4 by which this retarder 1 is fixed to a gearbox housing either directly either indirectly, here via a speed multiplier identified by 6.
• This casing 2 which is fixed, contains a rotary shaft 7 which is coupled to a transmission shaft not visible in the figure, such as a main transmission shaft to the wheels of the vehicle, or secondary such as a secondary output shaft of a gearbox via the speed multiplier 6.
• a current generator which comprises fixed or stator primary coils 8 which surround secondary rotor windings, integral with the rotary shaft 7.
• These secondary windings are symbolically represented in FIG. 2, being identified by the reference 5.
• These secondary windings 5 here comprise three separate windings 5A, 5B and 5C for delivering a three-phase alternating current having a frequency conditioned by the speed of rotation of the shaft. rotary 7.
• An internal jacket 9 of generally cylindrical shape is mounted in the main casing 2 while being slightly spaced radially from the external wall of this main casing 2 to define an intermediate space 10, substantially cylindrical, in which a coolant liquid circulates from this jacket 9 .
• This main casing which also has a generally cylindrical shape, is provided with an inlet pipe 11 for coolant into the space 10 and a delivery pipe 12 for the coolant out of this space 10.
• This jacket 9 surrounds several inductor coils 13 which are carried by a rotor 14 rigidly secured to the rotary shaft 7.
• Each inductor coil 13 is oriented to generate a radial magnetic field, while having a generally oblong shape extending parallel to the tree 7.
• the jacket 9 and the body of the rotor 14 are made of ferromagnetic material.
• the casing is a moldable piece based on aluminum and seals intervene between the casing and the jacket 9, the cover 3 and the part 4 are perforated.
• the inductor coils 13 are electrically supplied by the secondary rotor windings 5 of the generator via a rectifier bridge carried by the rotary shaft 7.
• This rectifier bridge can be the one marked with 15 in FIG. 2, and which comprises six diodes 15A -15F, to rectify the three-phase alternating current from the secondary windings 5A-5C in direct current.
• This rectifier bridge can also be of another type, for example being formed from MOSFET type transistors.
• the rotor 14 carrying the induction coils 13 has the general shape of a hollow cylinder connected to the rotary shaft 7 by radial arms 16.
• This rotor 14 thus defines an annular internal space situated around the shaft 7, this internal space being ventilated by an axial fan 17 located substantially at the junction of the cover 3 with the casing 2.
• a radial fan 18 is situated at the opposite end of the casing 2 to evacuate the air introduced by the ventilator 17.
• the putting into service of the retarder consists in injecting into the primary coils 8 an excitation current coming from the electric network of the vehicle and in particular from the battery, so that the generator delivers a current on its secondary windings 5. This current then feeds the coils inductors 13 to produce a resistant torque for vehicle deceleration.
• the excitation current is injected into the primary coils 8 by means of a control unit 19, shown in FIG. 2, which is interposed between a source of electrical power for the vehicle, and the primary coils 8.
• the control unit 19 and the primary coils 8 are mounted in series between a mass M of the vehicle and a supply Batt of the vehicle battery.
• a diode D is mounted across the primary coils 8 so as to avoid the circulation of a reverse current in the primary coils.
• This control unit 19 includes an input capable of receiving a control signal representative of a level of deceleration torque requested from the retarder.
• This input can be connected to a lever or the like which is actuated directly by a driver of the vehicle.
• This lever can be gradually movable between two extreme positions, namely a maximum position corresponding to a request for maximum resistive torque, and a minimum position in which the retarder is not stressed.
• the retarder is controlled by the housing 19 to exert on the rotary shaft 7 a resistive torque proportional to the position of the lever, relative to the maximum available retarding torque.
• the input of the control unit 19 receives a control signal which corresponds to a value between zero and one hundred percent.
• This input can also be connected to a brake control unit which independently determines a retarder control signal.
• This brake control unit is then connected to one or more brake actuators available to the driver.
• the driver does not act directly on the retarder, but it is the brake control unit which controls, from different parameters, the retarder and the traditional brakes of the vehicle.
• the control unit 19 is an electronic unit comprising for example a logic circuit of the ASIC type operating at 5V, and / or a power control circuit capable of managing currents of high intensity.
• the control unit 19 determines a nominal intensity of excitation current to be injected into the primary coils 8, and it injects into the primary coils 8 an excitation current. whose intensity gradually increases until reaching the nominal value. The housing 19 then maintains this nominal current as long as the piloting signal is unchanged, that is to say as long as a resisting torque is requested from the retarder.
• the progressive increase, for a predetermined period, of the intensity of the excitation current is for example carried out in the form of a current ramp, that is to say a linear increase in the intensity up to to reach the nominal value.
• the control unit 19 controls the excitation current in order to make it increase progressively up to a nominal value.
• This progressive increase in intensity makes it possible to reduce the overvoltages at the terminals of the inductor coils, and therefore at the terminals of the rectifier 15 during each commissioning of the retarder.
• control unit 19 commands a progressive increase in the intensity of the excitation current for a duration which is greater than the time constant T2 of the secondary windings 5 and the time constant T3 of the inductor coils 13, such so that there is no overvoltage across the rectifier 15.
• the duration of the progressive increase is also greater than the time constant T1 of the primary coils.
• the predetermined period during which the control unit increases the excitation current is advantageously a period which is greater than T1, T2 and T3 for ensure that there is no overvoltage in the retarder when it is put into service.
• the predetermined duration of establishment of the excitation current is between one and ten times the longest time constant value among T1, T2 and T3, which makes it possible both to limit overvoltages and to ensure correct reactivity when the retarder is activated.
• the progressive increase in the excitation current during the predetermined duration can be controlled by the control unit 19 to be linear, by corresponding to a current ramp.
• the excitation current can increase quadratically with respect to time, exponential or trigonometric.
• the overvoltage is notably conditioned by the slope of variation of the excitation current during commissioning. This gradual increase in intensity
• the choice of a suitable evolution law further reduces the overvoltage at the terminals of the rectifier 15 so as to reduce the duration of establishment of the current to bring it as close as possible to the value of the longest time constant among T1 , T2 and T3.
• the intensity of the excitation current increases exponentially during commissioning, which makes it possible to reduce the duration of establishment of the excitation current to a value very close to that of the longest time constant. among Tl, T2 and T3.
• the invention thus makes it possible to limit the overvoltage at the terminals of the current rectifier, which makes it possible to reduce the manufacturing cost of the rectifier and increase its longevity.
• the invention also makes it possible to avoid deterioration of the induction coils and / or the secondary windings of the generator by reducing the voltages applied to them.
• the invention is not limited to the embodiments described. It applies in particular to a retarder comprising a current rectifier in the form of a bridge of MOSFET transistors.
• the number of generator phases which depends on the applications, can be greater than three as a variant.

Landscapes

• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Dynamo-Electric Clutches, Dynamo-Electric Brakes (AREA)
• Control Of Eletrric Generators (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=37049000

Family Applications (1)

Country Status (7)

Families Citing this family (5)

Family Cites Families (4)

• 2005
  • 2005-12-09 FR FR0553819A patent/FR2894734B1/fr not_active Expired - Fee Related
• 2006
  • 2006-12-11 BR BRPI0618437A patent/BRPI0618437A2/pt not_active IP Right Cessation
  • 2006-12-11 MX MX2008007456A patent/MX2008007456A/es not_active Application Discontinuation
  • 2006-12-11 EP EP06841906A patent/EP1958320A2/de not_active Withdrawn
  • 2006-12-11 US US12/092,136 patent/US20090301829A1/en not_active Abandoned
  • 2006-12-11 WO PCT/FR2006/002701 patent/WO2007066019A2/fr not_active Ceased
  • 2006-12-11 CN CNA2006800450613A patent/CN101322306A/zh active Pending

Non-Patent Citations (1)

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